In a recent presentation at the Society for Vertebrate Paleontology's annual meeting, Michael Habib, a biomechanical paleontologist at UCLA, revealed groundbreaking findings about the extraordinary defensive capabilities of the nodosaur Borealopelta markmitchelli. The study shows that the armor of this Cretaceous-period herbivore could withstand forces equivalent to a high-speed car crash, offering new insights into dinosaur defense mechanisms.
Discovered in 2017 in a mine in Alberta, Canada, the exceptionally well-preserved fossil of Borealopelta markmitchelli has provided unprecedented details about armored dinosaurs. Unlike most fossils, which only preserve bone structures, this specimen revealed organic elements such as the color of its armor and traces of its last meal. Emma Schachner, an evolutionary biologist at the University of Florida who was not involved with the research, told Live Science, "It's stunningly beautiful, just extremely well preserved."
The nodosaur, which lived about 110 million years ago during the early Cretaceous period, was a large herbivorous dinosaur that could grow to be 18 feet (5.5 meters) long and weigh up to two tons. This armored dinosaur was covered with bony plates and spikes, overlaid with a thick layer of keratin—the material that makes up hair and fingernails. Previously, paleontologists assumed that the main protection of armored dinosaurs like nodosaurs and ankylosaurs was provided by a structure of bony plates covered only by a thin layer of keratin. However, the Borealopelta markmitchelli fossil reveals that the keratin layer played a very important role in protection.
The research team analyzed the well-preserved fossil, discovering that the keratin layer over the bone was nearly 6.3 inches (16 centimeters) thick—much thicker than previously anticipated. In contrast, the keratin sheath over a modern cattle horn is only 0.6 inches (1.5 centimeters) thick, according to Habib.
To test the armor's effectiveness, the researchers conducted several analyses. By looking at the structure and size of the keratin sheaths and comparing them to the keratin armor of modern animals like the quills of a porcupine.
The team further tested this by creating synthetic nodosaur armor and exposing it to forces similar to those generated by a predator attack. They used replica Acrocanthosaurus jaws to simulate the bite force of a large carnivorous dinosaur of that era. The results were impressive: the armor could withstand a force comparable to that of a high-speed car accident, over 125,000 joules per square meter—similar to the force of a high-speed car crash. "This thing could tank an F150 going at speed," Michael Habib told Live Science.
"Borealopelta is living in a world of big, meat-eating dinosaurs. They could bite really hard. If you have very stiff, brittle armor that's relying on bone and you hit it really hard, it's going to crack," Habib explained. The keratin layer provided flexibility, allowing the bony plates to remain intact even after a powerful blow. The keratin sheaths allow for flexibility and can easily be removed if they get damaged—similar to trimming a broken nail instead of needing to heal a living broken bone. "These animals were not wearing plate armor; they were wearing a bulletproof vest over plate armor," he said.
The well-preserved fossil also suggests that the armor may have been used during fights between males vying for female mates. The researchers proposed that the armor's capacity to absorb violent blows would have been an asset in these confrontations. "It's one of those enduring questions: Are they fighting each other, or are they fighting other animals? What they are determining is that it seems like it's more for animal-to-animal combat, within the same species," Schachner commented,
"Horned dinosaurs, with their armored and weaponized faces and heads—there's a very good chance they are using a lot more keratin than is often modeled," Habib said. The finding suggests many species of dinosaurs exhibited a range of defenses, including horns, claws, clubbed tails, or dorsal spines, and that keratin played a more significant role in their protection than previously understood.
"In a world where super-predators roamed in every corner of the forest, it was better to be well protected when one was a herbivore, even if one weighed several tons," the researchers observed.
Sources: Live Science, Futura Sciences, Gazeta.ru, SciencePost
This article was written in collaboration with generative AI company Alchemiq